Laundry Machine Drum Balancing Control to Reduce Spinning Vibration

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Solution Overview

Problem

Laundry machines generate significant noise and vibration during the spinning cycle due to unbalanced drum rotation, which is not effectively addressed by existing technologies.

Innovation Solution

A control method for a laundry machine that includes a balancing step where the drum is rotated at a constant speed after passing through a transient region, using a balancer with movable bodies to reduce unbalance and absorb vibrations, and a flexible suspension system to decouple the tub from the cabinet, allowing for relative movement and reducing vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the drum is accelerated to high RPM during the spinning cycle, then the productivity of the laundry machine is improved, but noise and vibration are significantly increased

Engineering Contradiction:
Improvespinning cycle efficiencyVSAvoidnoise and vibration
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies preliminary action by performing a balancing step before the main spinning operation. The drum is rotated at a constant speed (first rotation speed) for a predetermined time to allow the balancer to adjust and balance the drum before acceleration to high RPM. This preliminary balancing action prevents excessive vibration and noise during the subsequent high-speed spinning while maintaining productivity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements periodic action by incorporating multiple balancing steps during the spinning cycle. The drum is periodically decelerated to the first rotation speed for balancing, then accelerated to the second rotation speed for spinning. This periodic alternation between balancing and spinning phases ensures continuous vibration control while maintaining overall spinning efficiency and productivity.

Inventive Principle:
Principle #19Periodic action

2Object-generated harmful factors

If the drum is decelerated to perform balancing, then noise and vibration are reduced, but the spinning cycle time is increased

Engineering Contradiction:
Improvenoise and vibrationVSAvoidspinning cycle duration
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent applies partial action by performing balancing at specific critical phases rather than continuously. The drum is decelerated to the first rotation speed for balancing only when necessary (before initial spinning and periodically thereafter), rather than maintaining constant low-speed balancing throughout the entire cycle. This selective balancing approach reduces vibration effectively while minimizing time loss.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent utilizes parameter changes by dynamically adjusting the rotation speed between two distinct levels: the first rotation speed for balancing and the second rotation speed for spinning. The control unit changes these parameters based on the operational phase, allowing the system to optimize between vibration reduction and time efficiency by switching between speed states rather than operating at a single fixed speed.

Inventive Principle:
Principle #35Parameter changes

3Stability of the object's composition

If a rigid support system is used for the drum, then the structural stability is improved, but vibration transmission to the cabinet is increased

Engineering Contradiction:
Improvedrum support stabilityVSAvoidvibration transmission
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary element (the balancer mechanism) between the drum and the support structure. The balancer includes movable weights that can adjust their position to counterbalance vibrations generated during spinning. This intermediary balancing system absorbs and neutralizes vibration forces before they are transmitted to the rigid support structure and cabinet, thereby maintaining structural stability while reducing vibration transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies parameter changes by dynamically adjusting the mass distribution parameters of the balancer during operation. The movable weights in the balancer change their radial position to adapt to varying vibration conditions at different rotation speeds. This dynamic parameter adjustment allows the system to maintain optimal vibration cancellation across different spinning phases while working with the rigid support structure.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method significantly reduces noise and vibration during the spinning cycle by ensuring balanced drum rotation and effective vibration absorption, enhancing user experience and machine performance.

Implementation Method 1

a balancer (70) provided in the drum (30), and wherein the balancer (70) comprises a plurality of movable bodies (72)

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

a suspension assembly (180) connected to the driving unit (40), and wherein the tub (12) is flexibly supported by the suspension assembly (180) with respect to the cabinet (110)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2470710B1Control method of laundry machine
Publication Date: 2017.10.04 LG ELECTRONICS INC
  • EP2470710B1 patent drawingFigure 1
  • EP2470710B1 patent drawingFigure 2
  • EP2470710B1 patent drawingFigure 3

AI summary

The patent application discloses a control method of a laundry machine provided with a balancer. The method includes a balancing step of at least one time for rotating a drum (30) at a constant speed for a predetermined time by decelerating the drum (30) if the drum (30) is accelerated at a predetermined RPM or more. The balancing step is performed after a rotation speed of the drum (30) passes through a transient region of the laundry machine (100).